Recent materials research has suggested that the Carbon nanotubes are considered by some to be the most promising electron emitting materials because of their small tip radius (approx. 4 nm), which leads to a significant improvement in turn on voltage and current density over current devices. (See M. S. Wang et al., J. Phys. Chem. B 2006, 110, 9397-9042; N. Jonge et al., Nature 2002, 420, 393-395, 461; W. Zhu et al., Appl. Phys. Lett. 1999, 75, 873-875) In another example, lanthanum hexaboride (LaB6) nanowire synthesized by Zhang et al. shows current densities that are one order of magnitude larger than commercial W/ZrO tips (i.e., the brightest commercially available field emitting material) at more favorable working conditions (e.g., room temperature and 800 V versus 1800° C. and 3000 V). (H. Zhang et al., Adv. Mat. 2006, 18, 87-91)
However, in view of at least the foregoing, a need exists for the development of high aspect ratio nano-structures for use in electron emitting materials could enhance the emission properties of current devices while simultaneously making the working conditions more practical.